Traditionally, with motors, current is monitored in some way to prevent overloads. This may be a done with a thermally activated switch, commonly called a thermal protector. This device requires the overload condition to persist for some period of time to heat the thermal element, from several seconds to several minutes depending on the severity of the overload. It then requires a period of time to cool after the fault is removed before operation can resume. A second method uses a resistance element in series with the motor. The voltage across this resistor is proportional to the current and an electrical circuit can be design to shut off power to the motor when current flow exceeds a determined value. The disadvantage of this method is that power is dissipated in this resistance element which reduces overall system efficiency.